# Rieter

### Specification of fineness

#### Index

With the exception of wool and hair fibers, fiber fineness cannot be specified by reference to diameter as in the case of steel wire, because the section is seldom circular and is thus not easily measurable. As in the case of yarns and fibers, fineness is usually specified by the relation of mass (weight) to length:

$tex = \frac {mass (g)}{length (km)}$   or   $dtex = \frac {mass (dg)}{km}$

Whereas for man-made fibers dtex is used almost exclusively, the Micronaire value is used worldwide for cotton.

The fineness scale is as follows:

Mic VALUE
FINENESS
up to 3.1
very fine
3.1-3.9
fine
4.0-4.9